Not used but looks like that. The overall tendency of inncreasing number of providers offering cloud hosting such as utropicmedia.net and webhosting.uk.com tell about increasing demand, which indicates people's appreciation. It is like custom accopunt for everyone. Suitable for most type of content.

The answer depends on what cloud host you go with. Most "cloud" hosting packages are really only glorified VPS packages that still need to be refactored to be expanded/degraded. There's a few out there that are more like the cloud ideal where you can expand your service as needed. One thing to remember is that with most providers, you choose a service level and pay for that, and you can use up to those resources. If you need more, you pay for a burst, or a permanant upgrade, and you are given more resources. If you need less, you can remove some resources.

Still, there's not many that offer a true "pay as you use" service, mianly because it's damned hard to control. How fast do you want the CPU to run? Does it need to run full for every comamnd or just some? Do you need full bandwidth all the time or just sometimes? It's very complicated.